The invention relates in general to an absorption cooling system and more specifically to an improved heat exchanger for a high stage generator of an absorption chiller.
A direct-fired, double effect, absorption chiller/heater consists of an evaporator, absorber, condenser, high and low stage generators, separator, solution heat exchanges, refrigerant/solution pumps, burner and gas train assembly, purge, controls and auxiliaries. Water is used as the refrigerant in vessels maintained under low absolute pressure (vacuum). In the cooling mode, the chiller operates on the principle that under vacuum, water boils at a low temperature, thereby cooling the chilled water circulating through the evaporator tubes. A refrigerant pump is used to circulate the refrigerant water over the evaporator tubes to improve heat transfer.
To make the cooling process continuous, the refrigerant vapor must be removed as it is produced. To accomplish this, a lithium bromide solution (which has a high affinity for water) is used to absorb the water vapor. As this process continues, the lithium bromide becomes diluted, reducing its absorption capacity. A solution pump then transfers this weak (diluted) solution to the generators where it is reconcentrated in 2 stages to boil off the previously absorbed water.
In the high stage generator a significant amount of energy is lost in the exhaust flue gas. There has always been a continuing need in the field for improved efficiency in operating absorption chillers.
It is therefore a further object of the present invention to provide an absorption system having improved efficiency.
It is a further object of the present invention to provide an improved high stage generator for an absorption chiller.
It is an another object of the present invention to provide a system which utilizes lost energy in flue gas exhaust through a system which utilizes a flue gas recuperator. 